The important part of the students is that they experience a strong transition period with environmental changes characterized by an unhealthy diet and lack of physical activity that puts students at greater risk of weight gain. Overweight and obesity occurs in college students, according to the Centers for Disease Control (CDC), the prevalence of obesity in male students is 29.5% and in female students 32.6%. The purpose of this study was to analyze the relationship between eating habits and physical activity with the body mass index of S-1 UNS students. Type of observational analytic research with Cross Sectional approach. The subjects of this study are all students of S-1 UNS program in 2016 that is 24,826 people. Data were analyzed by chi square and multinomial logistic regression. The result of chi square correlation test showed that Eating Habits did not correlate significantly with Normal BMI - Thin or Normal BMT - Overweight (p = 0,193 & p = 0,446), whereas Physical Activity had significant relation with Normal BMT – Overweight (p = 0,029 ), But not related to normal BMI-thin (p = 0.655)..